The aims of this post-marketing observational study (PMOS) are to evaluate the time period needed to achieve > 30% decrease of intact parathyroid hormone (iPTH) compared to the initial values and to provide data on the tolerability and compliance of treatment with Zemplar (paricalcitol) capsules in the therapy of secondary hyperparathyroidism (SHPT) in patients with chronic kidney disease (CKD) stage 3 or 4 in conditions of routine clinical practice.